1. Field of the Invention
This invention relates generally to a single facer machine and, more particularly, to apparatus for the self-adjustment of the web guides that hold a corrugated medium web against the corrugator roll in a single-facer.
2. Description of the Prior Art
In the manufacture of corrugated board, the corrugated interliner is made by passing the web of paperboard material of the proper temperature and moisture content through the nip of a pair of coacting corrugating rolls having intermeshing splines running axially the length of the rolls. Conventionally, the web of paperboard passes partially around one roll, through the nip between the intermeshing spline teeth of the rolls where the web of paperboard material is deformed to the shape of the intermeshing teeth (corrugations or flutes are formed on the web), and then travels partially around the second corrugating roll. An adhesive roll parallel to and adjacent to the second roll applies adhesive to the tips of the flutes of the corrugated web. A pressure roll parallel to and adjacent to the second corrugating roll carries a smooth web of facing material and presses the facing web against the tips of the flutes having the adhesive thereon. The structure of an adhering smooth web and corrugated web is commonly called single faced paperboard.
If the corrugated web becomes disengaged from the second roll too early, malformations of the flutes may occur and these can reduce the quality of the corrugated paperboard being made. Guide means are conventionally used to hold the hot web closely to the second corrugating roll. These guide means are comprised of a plurality of thin crescent shaped strips of metal of an inner arc of a size substantially to fit around an arc of the second corrugating roll with minimal clearance and to extend from a head of the nip of the rolls to a point where the corrugated web comes in contact with the pressure roll. These guide means are generally spaced along the length of the roll from two to four inches apart. Conventionally, these guides are fixably held in place by means of rigid supports that are bolted to the structural members of the machine. Patent application Ser. No. 596,407 shows an improvement wherein the guide means are biased against the second corrugating roll, thereby permitting the guide means to adapt automatically and uniformly to different thicknesses and possible irregularities in the web.